# Deep learning-based acceleration of muscle water T2 mapping in patients with neuromuscular diseases by more than 50% - translating quantitative MRI from research to clinical routine

## TL;DR

This study shows that AI-based MRI techniques can cut scan time by over 50% for muscle T2 mapping in neuromuscular disease patients without losing accuracy.

## Contribution

Demonstrates the first application of CSAI AI acceleration for quantitative T2w MRI in neuromuscular diseases.

## Key findings

- CSAI 5x reduced scan time by over 50% compared to standard SENSE acceleration.
- T2w values from CSAI and SENSE showed excellent agreement (r = 0.99; ICC = 0.992).
- Both methods showed excellent intra- and inter-session reproducibility.

## Abstract

Quantitative muscle water T2 (T2w) mapping is regarded as a biomarker for disease activity and response to treatment in neuromuscular diseases (NMD). However, the implementation in clinical settings is limited due to long scanning times and low resolution. Using artificial intelligence (AI) to accelerate MR image acquisition offers a possible solution. Combining compressed sensing and parallel imaging with AI-based reconstruction, known as CSAI (SmartSpeed, Philips Healthcare), allows for the generation of high-quality, weighted MR images in a shorter scan time. However, CSAI has not yet been investigated for quantitative MRI. Therefore, in the present work we assessed the performance of CSAI acceleration for T2w mapping compared to standard acceleration with SENSE.

T2w mapping of the thigh muscles, based on T2-prepared 3D TSE with SPAIR fat suppression, was performed using standard SENSE (acceleration factor of 2; 04:35 min; SENSE) and CSAI (acceleration factor of 5; 01:57 min; CSAI 5x) in ten patients with facioscapulohumeral muscular dystrophy (FSHD). Subjects were scanned in two consecutive sessions (14 days in between). In each dataset, six regions of interest were placed in three thigh muscles bilaterally. SENSE and CSAI 5x acceleration were compared for i) image quality using apparent signal- and contrast-to-noise ratio (aSNR/aCNR), ii) diagnostic agreement of T2w values, and iii) intra- and inter-session reproducibility.

aSNR and aCNR of SENSE and CSAI 5x scans were not significantly different (p >  0.05). An excellent agreement of SENSE and CSAI 5x T2w values was shown (r =  0.99; ICC =  0.992). T2w mapping with both acceleration methods showed excellent, matching intra-method reproducibility.

AI-based acceleration of CS data allows for scan time reduction of more than 50% for T2w mapping in the thigh muscles of NMD patients without compromising quantitative validity.